I'll give it a thorough cleaning and see what happens.
Yes, exactly. There are many better chains available but it's sort of middle ground: average construction with the addition of o-rings. I think I'm going to try a very high quality non o-ring chain with an automatic oiler next as an experiment. They're very inexpensive compared to their o-ring/x-ring brethren so it will be fun to see what happens.
It seems that lots of big twins eat chains often and early compared to inline 4s. May be the same for big singles. I suspect it's the powerful, pulsy drive compared to the sewing machine smoothness that spells early demise for a chain.
Scott